From: Yafang Shao <laoar.shao@gmail.com>
To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
bristot@redhat.com
Cc: linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org,
Yafang Shao <laoar.shao@gmail.com>
Subject: [RFC PATCH 4/4] sched, rt: support schedstat for RT sched class
Date: Thu, 19 Nov 2020 11:52:30 +0800 [thread overview]
Message-ID: <20201119035230.45330-5-laoar.shao@gmail.com> (raw)
In-Reply-To: <20201119035230.45330-1-laoar.shao@gmail.com>
We want to measure the latency of RT tasks in our production
environment with schedstat facility, but currently schedstat is only
supported for fair sched class. This patch enable it for RT sched class
as well.
The schedstat statistics are define in struct sched_entity, which is a
member of struct task_struct, so we can resue it for RT sched class.
The schedstat usage in RT sched class is similar with fair sched class,
for example,
fair RT
enqueue update_stats_enqueue_fair update_stats_enqueue_rt
dequeue update_stats_dequeue_fair update_stats_dequeue_rt
put_prev_task update_stats_wait_start update_stats_wait_start
set_next_task update_stats_wait_end update_stats_wait_end
show /proc/[pid]/sched /proc/[pid]/sched
The sched:sched_stats_* tracepoints can be used to trace RT tasks as
well.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
---
kernel/sched/rt.c | 61 ++++++++++++++++++++++++++++++++++++++++++++
kernel/sched/sched.h | 2 ++
2 files changed, 63 insertions(+)
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index b9ec886702a1..a318236b7166 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1246,6 +1246,46 @@ void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
dec_rt_group(rt_se, rt_rq);
}
+static inline void
+update_stats_enqueue_rt(struct rq *rq, struct sched_entity *se,
+ struct sched_rt_entity *rt_se, int flags)
+{
+ struct rt_rq *rt_rq = &rq->rt;
+
+ if (!schedstat_enabled())
+ return;
+
+ if (rt_se != rt_rq->curr)
+ update_stats_wait_start(rq, se);
+
+ if (flags & ENQUEUE_WAKEUP)
+ update_stats_enqueue_sleeper(rq, se);
+}
+
+static inline void
+update_stats_dequeue_rt(struct rq *rq, struct sched_entity *se,
+ struct sched_rt_entity *rt_se, int flags)
+{
+ struct rt_rq *rt_rq = &rq->rt;
+
+ if (!schedstat_enabled())
+ return;
+
+ if (rt_se != rt_rq->curr)
+ update_stats_wait_end(rq, se);
+
+ if ((flags & DEQUEUE_SLEEP) && rt_entity_is_task(rt_se)) {
+ struct task_struct *tsk = rt_task_of(rt_se);
+
+ if (tsk->state & TASK_INTERRUPTIBLE)
+ __schedstat_set(se->statistics.sleep_start,
+ rq_clock(rq));
+ if (tsk->state & TASK_UNINTERRUPTIBLE)
+ __schedstat_set(se->statistics.block_start,
+ rq_clock(rq));
+ }
+}
+
/*
* Change rt_se->run_list location unless SAVE && !MOVE
*
@@ -1275,6 +1315,7 @@ static void __enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flag
struct rt_prio_array *array = &rt_rq->active;
struct rt_rq *group_rq = group_rt_rq(rt_se);
struct list_head *queue = array->queue + rt_se_prio(rt_se);
+ struct task_struct *task = rt_task_of(rt_se);
/*
* Don't enqueue the group if its throttled, or when empty.
@@ -1288,6 +1329,8 @@ static void __enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flag
return;
}
+ update_stats_enqueue_rt(rq_of_rt_rq(rt_rq), &task->se, rt_se, flags);
+
if (move_entity(flags)) {
WARN_ON_ONCE(rt_se->on_list);
if (flags & ENQUEUE_HEAD)
@@ -1307,7 +1350,9 @@ static void __dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flag
{
struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
struct rt_prio_array *array = &rt_rq->active;
+ struct task_struct *task = rt_task_of(rt_se);
+ update_stats_dequeue_rt(rq_of_rt_rq(rt_rq), &task->se, rt_se, flags);
if (move_entity(flags)) {
WARN_ON_ONCE(!rt_se->on_list);
__delist_rt_entity(rt_se, array);
@@ -1374,6 +1419,7 @@ enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags)
if (flags & ENQUEUE_WAKEUP)
rt_se->timeout = 0;
+ check_schedstat_required();
enqueue_rt_entity(rt_se, flags);
if (!task_current(rq, p) && p->nr_cpus_allowed > 1)
@@ -1574,6 +1620,12 @@ static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flag
static inline void set_next_task_rt(struct rq *rq, struct task_struct *p, bool first)
{
+ struct sched_rt_entity *rt_se = &p->rt;
+ struct rt_rq *rt_rq = &rq->rt;
+
+ if (on_rt_rq(&p->rt))
+ update_stats_wait_end(rq, &p->se);
+
update_stats_curr_start(rq, &p->se);
/* The running task is never eligible for pushing */
@@ -1591,6 +1643,8 @@ static inline void set_next_task_rt(struct rq *rq, struct task_struct *p, bool f
update_rt_rq_load_avg(rq_clock_pelt(rq), rq, 0);
rt_queue_push_tasks(rq);
+
+ rt_rq->curr = rt_se;
}
static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
@@ -1638,6 +1692,11 @@ static struct task_struct *pick_next_task_rt(struct rq *rq)
static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
{
+ struct rt_rq *rt_rq = &rq->rt;
+
+ if (on_rt_rq(&p->rt))
+ update_stats_wait_start(rq, &p->se);
+
update_curr_rt(rq);
update_rt_rq_load_avg(rq_clock_pelt(rq), rq, 1);
@@ -1648,6 +1707,8 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
*/
if (on_rt_rq(&p->rt) && p->nr_cpus_allowed > 1)
enqueue_pushable_task(rq, p);
+
+ rt_rq->curr = NULL;
}
#ifdef CONFIG_SMP
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 28986736ced9..7787afbd5723 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -649,6 +649,8 @@ struct rt_rq {
struct rq *rq;
struct task_group *tg;
#endif
+
+ struct sched_rt_entity *curr;
};
static inline bool rt_rq_is_runnable(struct rt_rq *rt_rq)
--
2.18.4
next prev parent reply other threads:[~2020-11-19 3:54 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-19 3:52 [RFC PATCH 0/4] sched: support schedstat for RT sched class Yafang Shao
2020-11-19 3:52 ` [RFC PATCH 1/4] sched: define task_of() as a common helper Yafang Shao
2020-11-19 3:52 ` [RFC PATCH 2/4] sched: make schedstats helpers not depend on cfs_rq Yafang Shao
2020-11-19 7:45 ` Mel Gorman
2020-11-19 11:24 ` Yafang Shao
2020-11-19 3:52 ` [RFC PATCH 3/4] sched: define update_stats_curr_start() as a common helper Yafang Shao
2020-11-19 3:52 ` Yafang Shao [this message]
2020-11-20 2:39 ` [RFC PATCH 4/4] sched, rt: support schedstat for RT sched class jun qian
2020-11-21 4:36 ` Yafang Shao
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201119035230.45330-5-laoar.shao@gmail.com \
--to=laoar.shao@gmail.com \
--cc=bristot@redhat.com \
--cc=bsegall@google.com \
--cc=dietmar.eggemann@arm.com \
--cc=juri.lelli@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rt-users@vger.kernel.org \
--cc=mgorman@suse.de \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=vincent.guittot@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).